Provided are: an epoxy compound having superior heat resistance and flame resistance of the cured product thereof; an epoxy resin containing the epoxy compound; a curable composition and cured product thereof; and a semiconductor sealing material. The epoxy compound is characterized by having a diarylene[b,d]furan structure, at least one of two arylene groups having a naphthalene skeleton, and both the arylene groups having a glycidyloxy group on the aromatic nucleus thereof.